Phenotypes

In what must be a sign of the times, Karageorgos et al. (2007) documented the first reported occurrence of this disorder in cattle and, in the same paper, also reported its molecular basis; in this case a missense mutation E452K (c.1354G>A) in the gene for alpha-N-acetylglucosaminidase (NAGLU).

The double-muscle trait in cattle is characterised by an increase in muscle mass of approx 20%, resulting in substantially higher meat yield, a higher proportion of expensive cuts of meat, and lean and very tender meat, for which a substantial premium is paid. The trait is autosomal recessive, and the locus has been given the symbol mh. It occurs at such a high frequency in Piedmontese and Belgian Blue cattle that it is characteristic of these...